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How to Build a PC - Memory Selection

By
Mike Clements, on October 4, 2013

Recently, my Corsair compatriot Jeff Checchi began publishing a series of blogs detailing How to Build a PC. He's shown us the fundamentals of planning a PC build, how to select a CPU and how to select a motherboard. He’s asked me to help out and provide a segment on how to select RAM, or random access memory for your PC. Selecting memory is pretty simple and there are things you need consider before making your selection so that you can make the most informed and strategic decision for your build.

Dominator Platinum is our flagship memory line and offers the ultimate in looks, features, and performance.

In his segment for motherboard selection, Jeff made the statement, “If your CPU is the “brain” of the system, the motherboard is the “heart,” and that is what we will be discussing in this article. If the CPU is the brain of your system then the memory represents the short term memory function a brain uses while processing and utilizing information. Selecting the proper memory kit is essential so that your CPU will be able to "think" as it is processing. Too little memory can cripple this ability and lead to a performance bottleneck. Higher frequency memory allows for faster memory performance. With respect to the amount of RAM you need, in some instances, more is not always better when going for maximum overclocking.

Selecting memory can be broken down into 3 parts. You will need to decide;

How much memory do I need for my system?

Do I intend to run my system at stock speed or will I overclock my memory?

Do I want to buy memory that will improve the aesthetics of my system?

How Much Memory Do I Need?

The Corsair Memory Finder is a great tool for selecting memory. It's simple to use and can streamline your entire memory selection process.

How much memory is needed will be dictated by both your software requirements and by the amount of memory your system can accept. Most modern desktop motherboards have 2, 4, or 8 memory slots with 4 being the most common. Memory kits also come in kits of 2, 4, or 8 modules depending on the platforms for which they were intended. This is convenient so that you can buy a matched set of memory that is tested together and guaranteed to work as the advertised specifications in your system. Modern memory controllers are quite adept at utilizing memory in all the available memory slots however; there is no harm in leaving 2 or 4 slots open if you can get the desired memory amount using 1/2 of the available slots on a 4 or 8 slot board. Boards with 2 memory slots will perform best with 2 memory modules.

Here is an X79 chipset based motherboard from the ASUS ROG line sporting 8 memory slots.

The most common number of memory slots for desktop motherboard is 4 as seen on the Gigabyte board below. This is true for both AMD and Intel based systems.

Micro-ATX and mini-ATX motherboards are becoming more popular as many different types of users migrate to smaller form factor systems. Many of these boards will have only 2 memory slots like this Z87 Stinger board from EVGA.

The typical PC user that uses their machine to check email, surf the internet, utilize social media etc will easily be served by 4GB of memory. Users that will be utilizing more demanding software such as video editing software or video games will want to go with a minimum of 8GB of memory. 16GB of memory is also a great option if you plan to do a great deal of multitasking. Power users or those with extreme system demands may opt for 32GB or even 64GB of RAM. If you are unsure of how to determine the memory requirements for your usage, most software and games provide their minimum and optimum system specifications on the box or on their web sites.

Important Note: Be sure to keep your specific version of Windows in mind during your selection process if you are a Windows user. 32bit versions of Windows cannot utilize more than 4GB of memory.

About Overclocking...

After you select the amount of memory, you’ll then need to select memory that fits your overclocking needs. If you prefer not to overclock then your memory needs to simply be able to operate at the stock speed set by your memory controller. If you do wish to overclock, then you must decide on your overclocking goals. You'll be able to determine these things by doing your homework as we discussed in the CPU how to segment.

If you are not familiar with the term overclocking, it is the process of making a computer component run at a higher frequency or clock speed that it is rated for. For several years, DDR3 memory has been capable of operating at a much higher frequency than memory controllers at their stock frequency. When users want more memory performance, they can choose to overclock their memory controller. This can be done by manually adjusting BIOS parameters for the memory frequency and the memory timings which will give you better memory performance.

Modern motherboards overclock more easily than ever before. Most have performance or overclocking presets in the BIOS. So, you can check your motherboard specifications and check the frequency options given in the BIOS and use those to assist in selecting your memory. Your CPU will factor in as well, of course, so be sure to enter it into the equation.

It is never a bad decision to have memory that is capable of matching or exceeding the the top frequency of your memory controller. However, choosing memory that is rated much lower than your CPU's memory controller is capable of can cripple your memory overclock.

Intel XMP (XMP = Xtreme Memory Profiles) are overclocking presets available in the BIOS that have been certified by Corsair and Intel. These presets allow user to set automatic memory overclocking presets with 1 simple BIOS setting. Corsair maintains more XMP certified memory modules with Intel than all other memory manufacturers combined. Learn more about XMP HERE.

Here is an excerpt from the Intel site explaining XMP:

The Intel® Extreme Memory Profile

Intel® Extreme Memory Profile (Intel® XMP) allows you to overclock compatible DDR3 memory to perform beyond standard specifications. It’s designed to enhance the gaming features built into Intel® technology–based PCs. If you like to overclock and squeeze as much performance from your PC as possible, then memory based on Intel XMP gives you that extra edge you need to dominate—without breaking a sweat.1

How Intel XMP works

Predefined and tested Intel XMP profiles can be loaded via BIOS or a specific tuning application through a computer’s operating system. Often the easiest way to load Intel XMP profiles is using a tuning utility, which may be available depending on the particular board manufacturer. To learn whether a tuning utility is available on your system, you should contact the board manufacturer.

Using XMP is not required on Intel systems and XMP is not available on AMD based systems. However, users can manually tune and overclock their memory on either type of platform if they wish. Many enthusiasts actually do not use memory or overclocking presets and prefer to manually tweak and overclock their memory frequency and timings. So, be sure to select a memory kit that allows you to fully exploit the capabilities of your motherboard and CPU combo.

Making Your System Look Great!

With careful planning and selection, your memory can perform well and also look great while doing it.

The Dominator line has long set the standard in the industry for great performance, superior thermal characteristics, and awesome looks.

Corsair Vengeance Pro is a great choice for exploiting memory controllers and motherboards.

Users that wish to achieve the absolute maximum memory overclock will need to select memory kits that allow them to first achieve the desired frequency while also offering enough memory for their needs.Boards with 4 slots will allow higher frequencies with 2 modules than with 4. The same is true of boards with 8 slots; they will allow higher memory frequencies with 4 of the 8 slots filled due to the difference in loading on the memory controller.

Be sure to research the capabilities of your motherboard and the expected overclocking capabilities of your CPU. Some CPUs simply cannot achieve the highest frequencies and no CPU manufacturer is going to guarantee overclocking performance so careful CPU selection is critical.

Some of you use cases that do not have a windowed side panel. Also, some people do not put any emphasis on the aesthetics of their system. For them, any memory kit that will achieve their desired amount of memory and frequency is fine.

Our classic XMS design never goes out of style.

Others will want to look at the Vengeance, Vengeance Pro, Dominator, and Dominator Platinum lines. These kits offer a variety of ways to compliment the many motherboard color schemes and huge variety of PC lighting available.

You will need to decide how to balance your desired goals with your budget you set. If you do not have the "high end to ridiculous" budget that Jeff described in the planning segment, you will need to do your research and decide on where to compromise. With proper research, you will be able to select the perfect combination of CPU, motherboard, and memory. Your kit will provide you the proper amount of memory, great performance, and the looks to go with it.